accel/ivpu: Clear CDTAB entry in case of failure

Don't leave a context descriptor in case CFGI_ALL flush fails.
Mark it as invalid (by clearing valid bit) so nothing is left in
partially-initialized state.

Signed-off-by: Karol Wachowski <karol.wachowski@intel.com>
Reviewed-by: Jacek Lawrynowicz <jacek.lawrynowicz@linux.intel.com>
Reviewed-by: Jeffrey Hugo <quic_jhugo@quicinc.com>
Signed-off-by: Jacek Lawrynowicz <jacek.lawrynowicz@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241017145817.121590-5-jacek.lawrynowicz@linux.intel.com

drivers/accel/ivpu/ivpu_mmu.c

@@ -749,10 +749,17 @@ static int ivpu_mmu_cdtab_entry_set(struct ivpu_device *vdev, u32 ssid, u64 cd_d
 
 	ret = ivpu_mmu_cmdq_write_cfgi_all(vdev);
 	if (ret)
-		goto unlock;
+		goto err_invalidate;
 
 	ret = ivpu_mmu_cmdq_sync(vdev);
+	if (ret)
+		goto err_invalidate;
 unlock:
+	mutex_unlock(&mmu->lock);
+	return 0;
+
+err_invalidate:
+	WRITE_ONCE(entry[0], 0);
 	mutex_unlock(&mmu->lock);
 	return ret;
 }